In transferring dry fluid substances such as barite (drilling mud), an air stream generated by a blower is sometimes utilized to force the particulate product from the transport container to the product tanks at the drilling site. As the product is transferred, the air in the product tank must be vented to prevent a high pressure build-up. In order to prevent the emission of particulate product from the atmosphere during this venting, traditionally bag houses have been employed, wherein the vented air passes through a plurality of filter bags which collect the particulates therein. While filter bags remove most of the particulates form the vented air, the technology is relatively old and this means of filtration is not as efficient as other filter media employed in other areas. Many filter bags are often required to vent the quantity of air released during this process, and the bags must be changed frequently. Further, filter bags do not greatly dampen the noise created during the venting process, which can be deafening.
The following patents are considered to have at least some pertinence with regard to the system of the present invention:
______________________________________ Patent Number Inventor Date of Issue ______________________________________ 5571299 Tonn 11/05/1996 5421846 Klimczak 06/06/1995 5108473 Hayden 04/28/1992 4844665 Howell 07/04/1989 4790865 DeMarco 12/13/1988 4789387 Nemesi et al 12/06/1988 4759781 Olson 07/26/1988 4666472 Klimczak et al 05/19/1987 4445915 Robinson 05/01/1984 4388087 Tipton 06/14/1983 4218227 Frey 08/19/1980 4113449 Bundy 09/12/1978 4204849 Johnston 05/27/1980 3733790 Pierce 05/22/1973 3726066 Colley et al 04/10/1973 ______________________________________
U.S. Pat. No. 4,844,665 to Howell teaches a "Portable Industrial Filter System" teaching a filter bag assembly in a housing configured to filter barite or other dry fluid product from vented air generated during transfer of the product to a storage receptacle via blown stream of air generated by a blower, which carries the particles from the tank to the storage receptacle. Howell '665 also teaches the utilization of the same blown air stream utilized to transfer the product in a reverse stream through the filter, to dislodge particles from the filter. Howell is a low pressure system, and it is believed would not work in a high pressure, pneumatic transfer context.
U.S. Pat. No. 5,108,473 issued 1992 teaches a "Dust Collector with Atmospheric Back flush" wherein there is utilized cylindrical, replaceable filter elements which may be cleaned via backflow of pulsed air.
U.S. Pat. No. 5,571,299 issued 1996 teaches a "Dust Collector" comprising stacked, cylindrical filter elements, suspended in a filter housing.
U.S. Pat. No. 3,726,066 teaches a "Dust Collector" contemplates another system utilizing a cylindrical filter system in a housing including cleaning means in the form of a reverse burst of high pressure gas.
U.S. Pat. No. 4,759,781 teaches a "Filter and Dust Collecting Apparatus" utilizing a filter bag including an automatic timing arrangement for cleaning the filters.
U.S. Pat. No. 4,789,387 contemplates a dust collector utilizing cylindrical filter medium, which further utilities a burst from an air compressor for cleaning same.
U.S. Pat. No. 4,113,449 teaches a "Baghouse Cleaning Method" in a high pressure dust collector system.
Thus, while the prior art has contemplated backwashing filters, including cleaning filter bags via reverse flow, and the utilization of cylindrical stacked filters for air filtration is not entirely new, it would appear that the prior art fails to contemplate the system and improvements of the present invention. The deficiencies in the prior art and methods for venting process air and depressurizing high pressure vessels lie in the need for continuous venting and dust removal and silencing the noise associated with venting high pressure vessels. While the above noted technologies may be useable to some degree in a low pressure scenario, it is believed that said systems do not provide the capabilities and operational reliability and ease of use made possible by the present invention, especially when implemented in a high pressure system, as is the preferred embodiment of the invention.